1. Field of the Invention
The present invention relates to a wide band wireless communication system. More particularly, this invention relates to a channel allocation method for efficiently allocating channels in accordance with the quantity of data when transmitting data from a customer premises equipment unit to a head-end unit.
2. Description of the Related Arts
A conventional wide band wireless multimedia communication system generally includes a central office unit, a head-end unit, a hub outdoor unit, and a customer premises equipment unit.
The central office unit plays a role in exchanging data, managing customers, supervising a network, linking a network, connecting to an internet, and the like. The head-end unit communicates with the central office unit and transmits data to the customer premises equipment unit. In addition, the head-end unit handles data transmitted from the customer premises equipment unit, and provides the data to the devices in the central office unit. The hub outdoor unit modulates the data received from the head-end unit into a wireless signal, and receives a wireless signal from the customer premises equipment unit and relays the wireless signal to the head-end unit. The customer premises equipment unit is located in a customer""s house so that the customer can utilize a telephone, an internet, a television, etc.
In the conventional wide band wireless multimedia communication system constructed as above, the customer premises equipment unit has used only reserved channels when sending internet data. The way of sending the reserved channel-based data has had an advantage that customers can be stably provided with data, without delay. However, in light of the characteristics of an internet communication, the quantity of the data that customers send to the head-end unit is relatively smaller than the data received. Thus, the system is continuously occupying wireless channels even when a customer does not send data. This type of channel allocation makes resources which are limited to the system be not efficiently utilized.
To compensate for this problem, it was suggested that channels were occupied only when there were data to be sent, and after sending the data, channels were released for another customer""s use. In the case of sending data using only a contention time slot instead of a reserved time slot, there arise no problems when a traffic is light. However, as the number of customers increases, there arise a data conflict due to a contention time slot and a delay between the data cells which are to be successively sent, thereby data continuity being broken off.
It is an object of the present invention to provide a channel allocation method on performing a data communication in a wide band wireless multi-media communication system, which allocates selectively reserved time slots or contention time slots, according to the quantity of data to be sent.
To achieve the object, the present invention uses contention time slots for sending data if the quantity of the data is smaller than a critical value, or reserved time slots if the data quantity is greater than the critical value.
Hereinafter, a frame is the basic unit of data, which can be sent at a time.